Have you asked Cathay Photo? If they don't have, you may have to find from suppliers of cine equipment or maybe directly from Kodak. But these reels are quite long and you may have to cut your own length in a darkroom/darkbag.
The shop in Lucky Chinatown stocks Minox film, which I believe is 16 mm. I wonder if it's still within expiry date. That guy sells things very expensive, though.
